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James Spann: Snow for Alabama this week? Here’s what we know so far

TRENDING COLDER: The first surge of colder air moves into Alabama today; temperatures will hover around 50 degrees much of the day, with a sky featuring more clouds than sun. No rain expected. Tomorrow will be dry and cool, with a partly sunny sky and a high between 52 and 55 degrees for most places.

FRIGID FRIDAY: Things begin to get interesting Friday as true Arctic air arrives; it looks like temperatures will hover in the 30- to 34-degree range all day with a cloudy sky. This is some of the coldest air we have experienced so far this winter season. Very cold air is a certainty, but everybody wants to know about potential for wintry precipitation in the cold air, and that is the focus of this discussion.

METEOROLOGICAL SETUP: Most model guidance suggests the atmosphere will be cold enough for snow over the northern half of the state during the day Friday, but with limited moisture. Seems like two separate areas of precipitation will initiate Friday; some light snow over North Alabama with an upper feature, and rain for the southern half of the state as a weak low-pressure area forms in the northern Gulf of Mexico.

The most widespread precipitation will most likely come Friday night over the southern two-thirds of the state, with potential for some snow/sleet/freezing rain on the northern periphery across Central Alabama. It all ends early Saturday morning as the low lifts northeast.

There is decent agreement in the big picture, but huge model differences in the small-scale details that will determine the actual weather and impact for any given point. I have decided to hold off on putting together an accumulation potential/placement map until this afternoon; the local weather enterprise will conference early this afternoon and do our best to give you a unified message later today.

IMPORTANT POINTS: Longtime readers know I like to tell people what we know, and I don’t tell them what we don’t know. This is what we know this morning:

Moisture over the northern half of the state will be pretty limited, so snow amounts, if any, will most likely be light, less than one-half inch (if you see snow at all).

There is some chance that, on Friday night, a heavier strip of wintry precipitation could develop over Central Alabama, but there is no way now of knowing exactly where that happens. And this could be more sleet and freezing rain than snow. Guidance from NOAA’s Weather Prediction Center hints freezing rain problems could develop Friday night along I-85 from Montgomery toward Opelika. Freezing rain is simply rain that falls with temperatures at or below 32 degrees at the surface.

In terms of travel impact, light snow Friday morning could bring a few icy spots to North Alabama. But the highest potential for icy travel issues should come Friday night with temperatures dropping into the 20s over the northern half of the state.

Sure, anything can happen, but this is NOT an analog to Jan. 28, 2014 (snowmageddon). Snow was falling with temperatures near 20 degrees during that event; the ice accretion process on roads, as we have learned, is radically different with surface temperatures that cold. Temperatures will be in the 29- to 34-degree range Friday and Friday night. Yes, some icy travel is very possible, but it won’t be like the horrible day in January 2014.

Be sure and check Alabama NewsCenter and AlabamaWX later today for updates; don’t work with old information as you make plans, especially if you are traveling. And, speaking of traveling, higher probabilities of more than 3 inches of snow are east of Alabama, across parts of Georgia and the Carolinas (their snow comes Saturday).

VERY COLD WEEKEND: The sky becomes partly sunny Saturday, and Sunday will be bright and sunny, but the weather will be very cold. We won’t get out of the 30s Saturday, and the low early Sunday and Monday will be in the 17- to 22-degree range.

NEXT WEEK: We start to warm up Monday afternoon, and the latest global model output shows a chance of rain returning to the state Wednesday with a short wave trough approaching.